GIPC and GAIP form a complex with TrkA: A putative link between G protein and receptor tyrosine kinase pathways
GIPC and GAIP form a complex with TrkA: A putative link between G protein and receptor tyrosine kinase pathways
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DOI：
10.1091/mbc.12.3.615
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发表时间：
2001-03-01
影响因子：
3.3
通讯作者：
Farquhar, MG
中科院分区：
文献类型：
--
作者：
Lou, XJ;Yano, H;Farquhar, MG
NGF通过促进酪氨酸激酶受体TrkA的活化来启动其大部分神经营养作用。在这里，我们描述了一种新的TrkA和GIPC，PDZ结构域蛋白之间的相互作用。GIPC通过其PDZ结构域与TrkA的质膜区域结合。GIPC的PDZ结构域也与GAIP相互作用，GAIP是一种RGS（G蛋白信号调节剂）蛋白。GIPC和GAIP是被认为参与囊泡运输的G蛋白偶联信号复合物的组分。在转染的HEK 293 T细胞中，GIPC、GAIP和TrkA形成可共沉淀的蛋白质复合物。TrkA和GAIP都与GIPC的PDZ结构域结合，但它们在PDZ结构域内的结合位点不同。内源性GIPC与TrkA受体的关联通过在稳定表达TrkA的PC 12（615）细胞中的免疫共沉淀来证实。通过免疫荧光，GIPC与位于分化的PC 12（615）细胞的神经突和细胞体中的逆行转运囊泡中的磷酸化TrkA受体共定位。这些结果表明，GIPC，像其他PDZ结构域蛋白，用于集群跨膜受体与信号分子。当GIPC在PC 1/2（615）细胞中过表达时，NGF诱导的促分裂原活化蛋白（MAP）激酶（Erk 1/2）磷酸化降低;然而，对Akt、磷脂酶C-γ 1或Shc的磷酸化没有影响。TrkA受体与GIPC和GAIP的关联加上GIPC对MAP激酶的抑制表明GIPC可能提供TrkA和G蛋白信号传导途径之间的联系。
NGF initiates the majority of its neurotrophic effects by promoting the activation of the tyrosine kinase receptor TrkA. Here we describe a novel interaction between TrkA and GIPC, a PDZ domain protein. GIPC binds to the juxtamembrane region of TrkA through its PDZ domain. The PDZ domain of GIPC also interacts with GAIP, an RGS (regulators of G protein signaling) protein. GIPC and GAIP are components of a G protein-coupled signaling complex thought to be involved in vesicular trafficking. In transfected HEK 293T cells GIPC, GAIP, and TrkA form a coprecipitable protein complex. Both TrkA and GAIP bind to the PDZ domain of GIPC, but their binding sites within the PDZ domain are different. The association of endogenous GIPC with the TrkA receptor was confirmed by coimmunoprecipitation in PC12 (615) cells stably expressing TrkA. By immunofluorescence GIPC colocalizes with phosphorylated TrkA receptors in retrograde transport vesicles located in the neurites and cell bodies of differentiated PC12 (615) cells. These results suggest that GIPC, like other PDZ domain proteins, serves to cluster transmembrane receptors with signaling molecules. When GIPC is overexpressed in PC12 (615) cells, NGF-induced phosphorylation of mitogen-activated protein (MAP) kinase (Erk1/2) decreases; however, there is no effect on phosphorylation of Akt, phospholipase C-gamma1, or Shc. The association of TrkA receptors with GIPC and GAIP plus the inhibition of MAP kinase by GIPC suggests that GIPC may provide a link between TrkA and G protein signaling pathways.